Control number of autocomplete results

Question

Is there any way to control number of results in an autocomplete field?

Usually node reference autocomplete fields provide 10 results. I want to increase that number.

Is there any global configuration available? How can I alter that number?

Answer 1

You will have to make a custom module to alter the result of autocomplete coming from node reference module. This example(taken from here) is for 20 result, you can increase/decrease according to your need.

function MYMODULE_menu_alter(&$menu) {
  if (isset($menu['nodereference/autocomplete'])) {
    $menu['nodereference/autocomplete']['page callback'] = 'MYMODULE_nodereference_autocomplete';
  }
}
function MYMODULE_nodereference_autocomplete($field_name, $string = '') {
  $fields = content_fields();
  $field = $fields[$field_name];
  $match = isset($field['widget']['autocomplete_match']) ? $field['widget']['autocomplete_match'] : 'contains';
  $matches = array();
  $references = _nodereference_potential_references($field, $string, $match, array(), 20);
  foreach ($references as $id => $row) {
    // Add a class wrapper for a few required CSS overrides.
    $matches[$row['title'] ." [nid:$id]"] = '<div class="reference-autocomplete">'. $row['rendered'] . '</div>';
  }
  drupal_json($matches);
}

Answer 2

In Drupal 8 you can configure the autocomplete limit match_limit directly in the field settings. This works fine for select2_entity_reference fields.

If you cannot modify the field settings because there are already data, export the field configuration with drush cex, modify the match_limit and import the modified config with drush cim.

(For url link fields, a different approach is needed: How to display more than 10 items in link widget autocomplete?)